The preparation of different types of reactive polyurethanes continues to be of interest in the coatings and other industries and in general for diverse applications where polymers with enhanced physical properties are sought. There are numerous reports describing the reaction of isocyanates with active methylene compounds.
For example, Moszner et al. in Polymer Bulletin, Vol. 33, pp. 43-49 (1994), Reaction Behaviour of Monomeric B-Ketoesters, reported the reaction of 2-acetoacetoxyethyl methacrylate (AAEM) with aromatic isocyanates to give adducts formed involving the active methylene moiety of AAEM. Reaction with aliphatic isocyanates failed.
Chlorosulfonyl isocyanate, reported to be the most reactive isocyanate known, is an electrophile which has been reported to react with the active methylene moiety of acetoacetic esters to give amides (Clauss et al., in Justus Liebigs Ann. Chem. (1974) pp. 561-592, Reaktionen der Aldelyde und Ketone mit Chlor- und Fluorsulfonylisocyanat).
Applicants are aware of no references which teach the present invention.